SU839587A1 - Apparatus for applying powdered polymeric material in electrostatic field - Google Patents

Description

(54) DEVICE FOR APPLICATION OF POWDERED POLYMER MATERIAL IN ELECTRIC FIELD

one

The invention relates to the production of polymer coatings and can be used in the electrical industry in the production of laminated plastics, varnished fabrics, etc.

A device for applying a powdered polymer material in an electric field is known, which comprises a working chamber with an electrode device placed inside it in the form of a two-row system of electrodes arranged in parallel rows with. alternating, polarity in height of each row and in a parallel row, pressurization chamber, device for electrization of the substrate, drying chamber, tempering and receiving mechanisms 1.

However, in this device, the electrodes are in direct contact with the powder-air mixture, which leads to the deposition of particles of the powder material on their surface. As a result, there is a reverse corona phenomenon and distortion of the pattern of the floor, which violates the stability of the application process until it stops.

Closest to the present invention is a device for applying a powdered polymer material in an electric field, comprising a working chamber, a charging device in the form of a two-row system of tubular electrodes with holes connected to a source of compressed gas, a device for electrifying the substrate, a drying chamber, tempering and receiving mechanisms 2.

However, in this device, the air leaving the hole in the tubular electrode only cleans the edges of the holes and does not prevent the ng electrode from depositing the powder, which does not allow for a stable and high-quality application. Violation of the aerodynamics of the fluidized bed also interferes with the qualitative application due to the presence of tubular electrodes in it, which are the cause of the vortex flows, impairing the uniformity of the layer deposited on the substrate.

In addition, the holes in the electrodes contribute to the appearance of a bipolar corona discharge, which increases the likelihood of interelectrode gap breakdown. These drawbacks limit the performance of the known device and are the reason for its insecurity in terms of fire.

The purpose of the invention is to increase the productivity and fire safety of the process.

This goal is achieved by the fact that in a device for applying a powdered polymer material in an electric field containing a working chamber, a charging device 6 is a two-row system of tubular electrodes with openings connected to a source of compressed gas, a device for electrifying the substrate, a drying chamber, a tempering and receiving mechanisms, tubular electrodes are provided with nozzles with coaxially mounted dielectric bushings and are placed in chambers mounted in a source connected with a source of compressed gas. the upper part of the working chamber and porous partitions separated from the latter, in which holes for dielectric bushings are made.

FIG. 1 shows a device, a general view; in fig. 2 shows section A-A in FIG. one.

The device comprises a working chamber 1 with a porous bottom 2 separating it from the pressurization chamber 3 connected to a source of compressed air. In the upper part of the working chamber 1, chambers 4 are mounted, inside of which tubular electrodes 5 are placed with nozzles 6 facing the substrate. The nozzles 6 are fitted with dielectric sleeves 7 that do not cover the openings of the nozzles. Chambers 4 with electrodes, 5 are arranged symmetrically and separated from the working area of the chamber 1 by porous partitions 8 in which holes are made. The sleeves 7, fastened with nuts 9, pass through the latter. The chambers 4 and the tubular electrodes 5 are connected by means of unions 10 and 11 to a source of compressed air. The potential is applied to the electrodes 5 from the power source 12 via the socket 13. The tubular electrodes 5 have alternating polarity along the height of the working chamber 1, each of which has the opposite polarity of the opposite electrode.

At the entrance to the chamber of pressurization 3 there is a device for electrifying the substrate 14, which consists of two rollers lined with fluoroplastic, and inside it there is a sealing device 15. A drying chamber 16 is placed at the exit of the working chamber 1.

The device is equipped with a release 17 and receiving 18 mechanisms.

The device works as follows.

A powder of a polymeric material is poured into the working chamber 1, and compressed air is supplied to the pressurization chamber 3, under the action of which the powder passes into a fluidized state. The dielectric substrate with the tempering mechanism 17 is pulled through the rollers of the electrification device 14 and the sealing device 15 into the working chamber 1, with the result

friction on the fluoroplastic surface of the rollers the substrate acquires static charges on both sides.

High voltage is applied to the tubular electrodes 5 from the power source 11,

moreover, electrodes symmetrically located with respect to the substrate supply a voltage of different polarity, as a result of which a strong electric field is created in the working zone of chamber 1, in which the powder is applied to the charged

substrate. In this case, the electrodes 5 are separated from the zone by nano porous partitions 8, which, practically without affecting the electrical characteristics of the floor, exclude the deposition of charged powder particles on

electrode nozzles 6 with sleeves 7 dramatically increase the gradient of tension in the immediate vicinity of itself. Particles entering this zone are subject to significant electrical forces and are intensively deposited on the substrate.

Simultaneously with the supply of voltage to the tubular electrodes 5 downward, through the fittings 10, compressed air is supplied, which, passing through the nozzles 6 and the sleeves 7, forms in the working zone of the chamber 1, in the area with the greatest gradient of intensity, the fields attracting with them particles of dusting and thereby accelerating the process of deposition of the latter on under. ozhku. Compressed air is also fed into the cavity of the chambers 4 through

0 fittings 11. From chambers 4, air passes into working chamber 1 through porous partitions 8, preventing particles from dropping onto them, which allows maintaining the optimal characteristics of the electric field.

5 The polymer-coated substrate is then passed through a drying chamber 14 into a receiving mechanism 18.

This technical solution, due to the presence on the electrodes of nozzles with dielectric bushings and porous partitions separating the electrodes from the powder application area, allows to create a non-uniform electrostatic field with high penetration gradients, improve fire and explosion safety, as well as improve aerodynamic characteristics in the application area -. All these advantages ensure a favorable course of the application process and cause an increase in the performance of the device and its fire safety.

Claims (2)

1. USSR author's certificate number 492122, cl. B 05 B 5/08, 1973. 2. USSR author's certificate No. 518883, cl. B 05 B 5/08, 1974 (prototype). //